1. Field of the Invention
This invention relates to a ring fuze for firearm ammunition, particularly for rifle cartridges, which fuze comprises a hollow fuze ring, which contains a primer.
2. Description of the Prior Art
Firearms which comprise a firing device which is disposed laterally of the chamber or comprise a firing pin which laterally enters the chamber must be furnished with ammunition provided with peripheral fuzes. It is already known to provide ring fuzes consisting of pocketlike annular grooves which are formed in the cartridge cases and filled with a primer (see U.S. Pat. Nos. 2,379,056 and 3,611,937). It has also been suggested to provide for caseless cartridges a ring fuze having a hollow fuze ring, which is closed in itself (see U.S. Pat. Nos. 3,808,973, 3,916,793, 4,236,451 and 4,537,134) and which consists of paper or another easily inflammable material and is filled with a primer, which can locally be squeezed to effect the detonation proper. But the manufacture of said known ring fuzes is expensive because they can be filled with the primer only by a complicated operation. Besides, they require the provision of a separate abutment consisting of the projectile which is fitted in the cartridge case, or of a specially designed cartridge case, so that the firing energy which has been applied by the firing pin is actually utilized to squeeze the primer and is not rendered ineffective by excessively large deforming work that is required. Said special abutments involve an additional expenditure and require the ring fuze to be arranged in a position which depends on the design of the cartridge which is employed or on the design of the abutment provided on said cartridge. That requirement renders the adaptation of the ring fuze ammunition to the firing systems of various firearms rather difficult.
Known cartridges for implements for shooting fasteners into workpieces comprise a spoollike ring fuze (see U.S. Pat. Nos. 2,931,039 and 3,060,855), which has an open peripheral groove that contains a primer. In that case too it is difficult to fill the open groove and the fuze is rather expensive because the primer must subsequently be pressed. There are also variations in the detonating characteristic and irregularlities occur in the detonation of the propellant charge, which is contained in the cartridge case and is accessible only thorugh rim notches. Because the primer must be squeezed between the spool and the cartridge case to effect a detonation, said fuzes cannot be used with plastic cases, which would damp the impact of the firing pin and may result in a failure to fire.